Stub out User Followers API
Implement the User Followers API

Update comments with links to API documentation
Remove API methods that were invalid
Refactor User Followers Client

Create ApiUrls methods for base Uri's
Add unit tests
Stub out observable User Followers API
Implement Observable User Followers API

Fix up Code Analysis errors
Add unit tests for the observable client
Add integration tests
Rename UserFollowersClient to FollowersClient
Tidy up doc comments

Remove unused CodeAnalysis Suppress messages
Fix up the mono projects
Merge pull request #343 from alfhenrik/user-followers-api

Implement User Followers API